/Engine/Plugins/FX/Niagara/Source/Niagara/Classes/NiagaraParameterCollection.h
The compile Id is an indicator to any compiled scripts that reference this collection that contents may have changed and a recompile is recommended to be safe.
[FNiagaraCompileHash](API\Plugins\NiagaraCore\FNiagaraCompileHash) GetCompileHash() const